11B.3 Observations of Low-Level Mesocyclone Redevelopment Using a Trajectory Mapping Technique

Wednesday, 7 November 2012: 2:00 PM
Symphony II (Loews Vanderbilt Hotel)
Daniel P. Betten, CIMMS/Univ. of Oklahoma, Norman, OK ; and M. I. Biggerstaff

A dual-Doppler dataset was collected on the 29 May 2004 Geary, OK tornadic supercell by a pair of C-Band SMART radars with analyses every 3 minutes and a horizontal resolution of 750 meters. The scale of the low level mesocyclone (~7km in diameter) and the slow storm motion (~12 m/s) and evolution allow for the calculation of Lagrangian trajectories over the dissipation stage of this tornadic mesocyclone as well as the development stage of the next mesocyclone. The mapping of trajectories allows for the examination of hundreds of trajectories at a single time, displaying height, wind, or vorticity information at a point in the past or integrated over time.

The evolution of the mapped trajectories from the 29 May storm revealed periodic surges of inflow and forward flank air around the low level mesocyclone that coincided to changes in the mesocyclone motion, strength and size, espically leading up to and during the occlusion stage. Analyses from the dissipation and redevelopment stage of the low-level mesocyclone will be presented that demonstrate that these surges of low level air continue to play an integral role during the redevelopment of the low-level mesocyclone.

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